[Saber doesn't believe she's seen so emotion displayed on him, aside from key circumstances. It makes her realize that he sincerely feels so, rather than simply pacifying and trying to smooth things over to feel better. And it's touching in a way, that he reacts like that on her behalf, so how can she do anything less than respond with honesty in kind?]
Truthfully... all I can do is bide my time here, and keep watch until a chance comes. I do not have objections if you wish for our partnership to remain until that time-- so long as it remains only that.
[It's clearly still worrying her what she feels that "partnership" has become. He should never have come to see her as a person... and maybe she really didn't help with that point. So she has to begin to correct it, and herself, from now on]